In the related art, as a conventional contact switching device, for example as shown in FIG. 5A of JP 2012-104356 A, a pair of through holes 61a is provided on the upper surface of a container 61 made of a heat-resistant material such as ceramic. Then, fixed terminals 33, 33 are respectively inserted and brazed into the pair of through holes 61a. Further, a yoke body 63 is located between the pair of fixed terminals 33, 33, and fixed to the inner upper surface of the container 61. The yoke body 63 has a substantially parallelepiped shape and is made of a magnetic material such as soft ion.
When movable contacts 34, 34 provided in a movable contactor 35 come in contact with the fixed contacts 32, 32, respectively, to allow an electric current to flow, a magnetic field is generated in the movable contactor 35. A holder 81 is thereby attracted to the yoke body 63, to reduce electromagnetic repulsive force that is generated between the movable contact 34 and the fixed contact 32. As a result, the reduction prevents a decrease in contact pressure, and prevents welding of the movable contact and the fixed contact 32 in association with an increase in contact resistance. Further, with generation of the electromagnetic repulsive force, the movable contact 34 and the fixed contact 32 are opened and an arc is generated, thereby preventing the welding of the movable contact 34 and the fixed contact 32.
However, in the above contact device, the yoke body 63 needs to be fixed, for example by brazing, to the inner upper surface of the box-shaped container 61. Hence, the fixing operation requires proficient skills and an assembly operation takes time, resulting in low productivity and high manufacturing cost.
Further, in the foregoing assembly operation, an assembly error easily occurs and the high positioning accuracy is hardly achieved, thus causing a problem that operation characteristics easily vary.